Damping device

ABSTRACT

A damping device, in particular for damping or avoiding pressure surges, such as pulses, in hydraulic supply circuits, preferably in the form of a silencer, having a damping housing ( 1 ) which surrounds a damping chamber and has at least one fluid inlet ( 35 ) and at least one fluid outlet ( 41 ) and a fluid receiving chamber which extends between the fluid inlet ( 35 ) and the fluid outlet ( 41 ), wherein, during operation of the device, a fluid flow crosses the damping chamber in a throughflow direction ( 11 ), coming from the fluid inlet ( 35 ) in the direction of the fluid outlet ( 41 ), and wherein at least parts of the fluid receiving chamber extend in at least one extent direction transversely with respect to the throughflow direction ( 11 ), is characterized in that more than one fluid receiving chamber is arranged one after the other in the throughflow direction ( 11 ) and in that the fluid receiving chamber which is first upstream and the fluid receiving chamber which is last downstream immediately adjoin the fluid inlet ( 35 ) and the fluid outlet ( 41 ), respectively.

The invention relates to a damping device, in particular for damping or avoiding pressure surges, such as pulsations, in hydraulic supply circuits, preferably in the form of a silencer, having a damping housing which surrounds a damping chamber and has at least one fluid inlet and at least one fluid outlet and a fluid receiving chamber which extends between the fluid inlet and the fluid outlet, wherein, during operation of the device, a fluid flow crosses the damping chamber in a throughflow direction, coming from the fluid inlet in the direction of the fluid outlet, and wherein at least parts of the fluid receiving chamber extend in at least one extension direction transversely with respect to the throughflow direction.

Damping devices of this kind are state of the art. Such hydraulic dampers, which are also referred to as sound dampers or silencers, serve to reduce oscillations, which are generated by pressure pulsations, to which a corresponding hydraulic system is repeatedly subjected, in particular due to the operation of hydraulic pumps. As is disclosed in the document DE 102 17 080 C1, the known damping devices of this kind have a damping housing in the form of a circular cylinder, which is rounded in a spherical manner at both axial end regions, with the fluid inlet and the fluid outlet being located coaxial to the cylinder axis on a respective end region. As the damping chamber, which the fluid flow crosses from the fluid inlet to the fluid outlet, a damping tube is provided in such damping devices, which extends coaxially between the fluid inlet and the fluid outlet and which, in the tube wall, has openings to the fluid chamber surrounding the tube. According to the cylinder diameter, the fluid chamber is radially expanded relative to the axial throughflow direction defined by the damping tube.

On the basis of this prior art, the problem addressed by the invention is to provide a damping device of the type considered, which, while having a simple construction, is distinguished by an advantageous operational behavior.

According to the invention, this problem is solved by means of a damping device having the features of Claim 1 in its entirety.

According to the characterizing part of Claim 1, a significant distinguishing feature of the invention is that more than one fluid receiving chamber is arranged one after the other in the throughflow direction and in that the fluid receiving chamber which is first upstream and the fluid receiving chamber which is last downstream immediately adjoin the fluid inlet or the fluid outlet. Thanks to the direct connection of the fluid receiving chambers to the fluid inlet or fluid outlet and the resulting omission of a damping tube, the device according to the invention is firstly distinguished by a simplified construction. Furthermore, the presence of more than one fluid receiving chamber makes it possible to better tune the damping device to different pulsation frequencies. This is advantageous in particular in the case of variable-speed drives, for example in the form of screw compressors, which produce a large range of frequencies as an excitation spectrum.

In particularly advantageous exemplary embodiments, the fluid receiving chambers expanded transversely relative to the throughflow direction are formed by disk-shaped cavities inside the damping housing, with disk-shaped cavities being able to be formed cylindrical or as polygons, while other shapes, for example oval contours, can also be considered for a targeted frequency tuning.

The respective cavities can have the same volumes and the same contours or can be formed differently with respect to volumes and/or contours.

In particularly advantageous exemplary embodiments, the cavities can be closed by boundary walls of the damping housing that extend parallel to one another, with parts of the fluid inlet and of the fluid outlet extending in alignment with these boundary walls in the damping housing and with the fluid inlet and fluid outlet formed as damping housing borings being able to have an identical diameter and said diameter being able to correspond to the spacing between the boundary walls.

The arrangement can particularly advantageously be such that the damping housing is formed in several pieces and such that the following components are provided:

-   -   a base part, which receives pot-like central recesses with the         one set of boundary walls and the fluid inlet and fluid outlet,         and     -   flange-like cover parts which, with the other boundary walls,         which are part of engagement pieces, engage in a flush manner in         the central recesses of the base part in the case of cover parts         fixed to the base part.

For the purpose of sealing the cavities relative to the environment, it is possible to arrange a sealing device on the engagement piece of the cover parts, which sealing device is in particular in the form of a sealing ring inserted into a circumferential groove, which seals the respective cavity as a component of the central recesses relative to the environment.

For a pressure-tight formation of the damping housing, the cover parts can have, lying opposite diametrical to their vertical axis, several penetration bores which, penetrated by fixing screws, fix the cover parts to the base part, with the arrangement advantageously being able to be such that the fixing screws, while leaving the region of the fluid inlet and the fluid outlet free, are arranged uniformly along an external circumference of the cover parts on the damping housing, which surrounds the disk-like fluid receiving chambers.

In advantageous exemplary embodiments, two cavities are provided consecutively in the throughflow direction, which are connected to one another by means of a fluid passage which, aligned with the fluid inlet and fluid outlet of the damping housing, is located in a wall section of the base part and which has the same diameter as the fluid inlet and the fluid outlet.

For the connection to a corresponding hydraulic system, it is possible to provide, on the fluid inlet and/or on the fluid outlet on the damping housing, a receptacle for a sealing ring, which surrounds the fluid inlet and/or the fluid outlet. In the manner of a fixing block, the damping housing can be fixed to third components by means of several fixing bolts, which surround the region of the fluid inlet and/or the fluid outlet.

The invention is explained in detail below with reference to an exemplary embodiment depicted in the drawings, in which:

FIG. 1 shows a perspective oblique view which, relative to a practical embodiment, is depicted downscaled with a scale of approximately 1:3, of an exemplary embodiment of the damping device according to the invention;

FIG. 2 shows a top view, depicted double the size of FIG. 1, of the exemplary embodiment;

FIG. 3 shows a longitudinal section of the exemplary embodiment along the intersection line III-III of FIG. 2;

FIG. 4 shows a partial view of only the fluid outlet-comprising connection region of the damping housing of the exemplary embodiment and

FIG. 5 shows a partial view, corresponding to FIG. 4, of the fluid inlet-comprising connection region.

With reference to the drawings, the invention is explained on the basis of the exemplary embodiment of a so-called silencer, which is provided to reduce the oscillations, which are produced by pulsations in hydraulic fluids subject to high pressure, for example in the region of 200 bar. The basic mechanical construction corresponds to a silencer provided for such an application, as is described as subsequently published prior art in the patent application DE 10 2014 005 822.0. In the present figures, the exemplary embodiment of the damping device is depicted in the assembled state. As can be best seen from FIG. 3, the damping housing 1 depicted in these figures consists of three main parts, namely, a base part 3 and cover parts 5 and 7, which are formed as identical parts. As FIGS. 1 and 2 show, the base part 3 has the contour of a rectangle having rounded corner regions 9 with a longitudinal axis 11, the extension of which corresponds to the throughflow direction of the fluid, which flows into the device from the end side 13 lying on the left-hand side in the figures and 10 leaves said device at the opposite end side 15. For the formation of the fluid receiving chambers 17 and 19, the base part 3 has two central recesses 21 and 23 (cf. FIG. 2), which are formed by circular, pot-like depressions, which are delimited by unrecessed, surrounding wall parts 25 (FIG. 3) of the base part 3. The central recesses 21, 23 are closed at the base by boundary walls 27 and 29 of the base part 3 which extend in a common plane. For the purpose of limitation of the fluid receiving chambers 17 and 19 having a disk-like shape, the cover parts 5 and 7 with their planar bottom side form top boundary walls 31 and 33 which, in the case of cover parts 5 and 7 mounted on the base part 3, extend in a plane parallel to the boundary walls 27 and 29. The fluid inlet 35 is located on the end side 13 of the base part 3 which lies on the left-hand side in the drawings, which fluid inlet is aligned with the boundary walls 27 and 31, so that the diameter of the fluid inlet 35 corresponds to the thickness of the circular disk-shaped fluid receiving chamber 17.

The circular disk-shaped cavity forming the second fluid receiving chamber 19, which is formed in the central recess 23 of the base part 3, is connected to the fluid receiving chamber 17 which is first upstream by means of a fluid passage 37, which is located in the wall section 39 of the base part 3 which lies centrally between the end sides 13 and 15. The fluid passage 37 is coaxial to the axis 11 and has the same diameter as the fluid inlet 35. In the depicted exemplary embodiment, both fluid receiving chambers 17 and 19 are formed by circular central recesses 21 and 23 of the same type and they therefore have the same volumes. In the end side 15 lying on the left in the drawings, the fluid outlet 41 is located in the wall part 25 of the base part 3, which fluid outlet, like the fluid inlet 35 and the fluid passage 37, is coaxial to the axis 11 and thus to the throughflow direction and has the same diameter as the fluid inlet 35 and the fluid passage 37.

As can be seen from FIG. 3, the cover parts 5 and 7 are designed as flange-like identical parts. Starting from a top side, which, in the state mounted on the base part 3, overlaps the wall parts 25 of said base part and the wall section 39, the cover parts 5 and 7 each have a projecting engagement piece 43, which is formed circular cylindrical and, in the case of a position mounted on the base part 3, engages in a fitting manner in the central recesses 21 or 23. Each engagement piece 43 has a circumferential annular groove 45, in which a sealing ring 47 is seated, which seals the engagement pieces 43 relative to the wall parts 25 and to the wall section 39 of the base part 3 and thus seals the fluid receiving chambers 17 and 19 relative to the environment.

For the screwing of the cover parts 5, 7 to the base part 3, threaded bores are formed in said base part, which are not visible in the drawings. For eight fixing screws 51 of each cover part 5, 7, these threaded bores are arranged in partial circular arcs, which surround the central recesses 21 and 23 and by means of which the cover parts 5, 7 can be fixed to the base part 3 in such a way that they adjoin one another with their flat side 53 at the central wall section 39 of the base part 3. In the region opposite the flat side 53, the cover parts 5, 7 are shaped such that, in the mounted state, they are adapted to the outer contour of the base part 3, with flat sides 55 of the cover parts 5, 7 respectively being flush with the end side 13 and the end side 15 of the base part 3 at the fluid inlet and the fluid outlet 35 and 41 and with a step-free outer shape being formed also in the rounded corner regions 9 also.

For the attachment of the damping housing 1 to corresponding third components, in the depicted exemplary embodiment at the end side 15 lying on the right-hand side in the drawings threaded bolts 57 are provided arranged symmetrical to the fluid outlet 41. In addition, a receiving groove 59 for a sealing ring is formed at the opposite end side 13 at the fluid inlet 35. For coupling connections, fixing bores 61 are arranged at the end side 13 in a symmetrical arrangement relative to the fluid inlet 35.

It shall be understood that, in a corresponding manner, a sealing arrangement can be provided at the end side 15 assigned to the fluid outlet 41. The symmetrical housing construction also allows the interchanging of the inlet side and the outlet side, potentially with changed sealing geometries. Thanks to the disk-shaped damping chambers with a cavity expanded transverse to the actual throughflow direction, a silencer with high efficiency is obtained, which has a low weight relative to its settable fluid volume. Furthermore, there is only a slight amplification, if any, between the silencer and a hydraulic pump connectable thereto.

In one embodiment of the damping device according to the invention, which is not depicted in detail, it is possible for the individual, consecutively arranged damping chambers 17, 19 to be differently designed with respect to their volume, in order to thus create damping chambers of different sizes, so that individual frequency bands with different frequencies can be effectively dampened, with one damping chamber 17 being able to be assigned to the one frequency band and the other damping chamber 19 being able to be assigned to the comparatively different type of frequency band. Furthermore, in an additional consecutive arrangement, which is likewise not depicted, a further third damping chamber and, if appropriate, additional damping chambers can be connected to the two first damping chambers 17, 19, if appropriate with changed volumes, so that, starting from a damping chamber with the smallest volume to a largest damping chamber connected thereto in a media-conducting manner, within the chain a relief of the pressure sequence of the media flow takes place, so that effective damping effects can be generated in this respect also. There is no equivalent of this solution in the prior art. 

1. A damping device, in particular for damping or avoiding pressure surges, such as pulsations, in hydraulic supply circuits, preferably in the form of a silencer, having a damping housing (1) which surrounds a damping chamber (17,19) and has at least one fluid inlet (35) and at least one fluid outlet (41) and a fluid receiving chamber (17, 19) which extends between the fluid inlet (35) and the fluid outlet (41), wherein, during operation of the device, a fluid flow crosses the damping chamber (17, 19) in a throughflow direction (11), coming from the fluid inlet (35) in the direction of the fluid outlet (41), and wherein at least parts of the fluid receiving chamber (17, 19) extend in at least one extension direction transversely with respect to the throughflow direction (11), characterized in that more than one fluid receiving chamber (17, 19) is arranged one after the other in the throughflow direction (11) and in that the fluid receiving chamber (17) which is first upstream and the fluid receiving chamber (19) which is last downstream immediately adjoin the fluid inlet (35) or the fluid outlet (41).
 2. The damping device according to claim 1, characterized in that each fluid receiving chamber forms a disk-like cavity (17, 19) inside the damping housing (1).
 3. The damping device according to claim 1, characterized in that the respective disk-like cavity (17, 19) is formed cylindrical or as a polygon.
 4. The damping device according to claim 1, characterized in that cavities (17, 19) having the same volumes and the same contours are provided.
 5. The damping device according to claim 1, characterized in that cavities (17, 19) having different volumes and/or different contours are provided.
 6. The damping device according to claim 1, characterized in that the cavities (17, 19) are closed by boundary walls (27, 29, 31, 33) of the damping housing (1) that extend parallel to one another and in that parts of the fluid inlet (35) and of the fluid outlet (41) extend in alignment with these boundary walls (27, 29, 31, 33) in the damping housing (1).
 7. The damping device according to claim 1, characterized in that the fluid inlet (35) and the fluid outlet (41) formed as damping housing bores have identical diameters with said diameter corresponding to the spacing between the boundary walls (27, 29, 31, 33).
 8. The damping device according to claim 1, characterized in that the damping housing (1) is formed in several pieces with a base part (3), which receives pot-like central recesses (21, 24) with the one set of boundary walls (27, 29) and the fluid inlet (35) and fluid outlet (41), and with flange-like cover parts (5, 7) which, with the other boundary walls (31, 33), which are part of engagement pieces (43), engage in a flush manner in the central recesses (21, 23) of the base part (3) in the case of cover parts (5, 7) fixed to the base part (3).
 9. The damping device according to claim 1, characterized in that a sealing device, in particular in the form of a sealing ring (47) inserted into a circumferential groove (45), is arranged on the engagement piece (43) of the cover parts (5, 7), which sealing ring seals the respective cavity (17, 19) as a component of the central recesses (21, 23) relative to the environment.
 10. The damping device according to claim 1, characterized in that the cover parts have, lying opposite diametrical to their vertical axis, several penetration bores which, penetrated by fixing screws (51), fix the cover parts (5, 7) to the base part (3).
 11. The damping device according to claim 1, characterized in that the fixing screws (51) while leaving the region of the fluid inlet (35) and the fluid outlet (41) free, are arranged uniformly along an external circumference of the cover parts (5, 7) on the damping housing (1), which surrounds the disk-like fluid receiving chambers (17, 19).
 12. The damping device according to claim 1, characterized in that two cavities (17, 19) are provided consecutively in the throughflow direction, which are connected to one another by means of a fluid passage (37) which, aligned with the fluid inlet (35) and fluid outlet (41), is located in a wall segment (39) of the base part (3) and which has the same diameter as the fluid inlet (35) and the fluid outlet (41).
 13. The damping device according to claim 1, characterized in that a receptacle (59) for a sealing ring is provided at the fluid inlet (35) and/or fluid outlet (41) in the damping housing (1), which sealing ring surrounds the fluid inlet (35) and/or the fluid outlet (41).
 14. The damping device according to claim 1, characterized in that, in the manner of a fixing block, the damping housing (1) can be fixed to third components by means of several fixing bolts (57), which surround the region of the fluid inlet (35) and/or the fluid outlet (41). 